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United States Patent | 5,162,675 |
Olsen ,   et al. | November 10, 1992 |
A peripheral adapter board and circuit which is capable for operation with two different personal computer bus architectures is disclosed. The preferred peripheral function for the board and circuit is a terminal emulator, which allows a personal computer into which the board is plugged to function as a terminal for a mainframe or minicomputer. Edge connectors or contacts are provided on opposite side edges of the board; each one of the edge connectors is compatible with a different computer bus. The adapter board may be flipped over to plug into either computer bus. A removable, repositionable connector board assembly is provided at one end of the board, for mounting communications connectors in a position accessible from the back panel of a host personal computer. The connector board may be repositioned to maintain the orientation of the communications connectors with respect to the personal computer back panel when the adapter board is flipped over to plug into a different computer bus. Circuitry is provided for detecting the particular computer bus into which the adapter board is plugged, and for providing appropriate address, data, and control signals associated with the selected computer bus.
Inventors: | Olsen; Derek S. (San Jose, CA); Cavaness; Richard D. (Freemont, CA); Snyder; Gail R. (San Jose, CA) |
Assignee: | Digital Communications Associates, Inc. (Alpharetta, GA) |
Appl. No.: | 339186 |
Filed: | April 14, 1989 |
Current U.S. Class: | 326/37; 326/86; 326/101; 361/684; 361/786; 439/62 |
Intern'l Class: | G06F 013/38 |
Field of Search: | 307/465,276,303.1,475 361/395,399,413,415 439/59,62,65 364/200 MS File,900 MS File |
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4704599 | Nov., 1987 | Kimmel et al. | 361/413. |
4885482 | Dec., 1989 | Sharp et al. | 307/465. |
Foreign Patent Documents | |||
08801008 | Sep., 1988 | BE. | |
0936288 | Sep., 1963 | GB | 361/413. |
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______________________________________ SS0 SS1 Cycle Type ______________________________________ L L JR CPU RAM cycle L H MCA/PCA/JR ROM cycle H L MCA/PCA RAM cycle H H external cycle ______________________________________